The Present invention relates to transmissions in general, and more particularly to improvements in continuously or infinitely variable speed transmissions of the type disclosed, for example, in commonly owned U.S. Pat. No. 5,667,448 granted Sep. 16, 1997 to Oswald Friedmann for "POWER TRAIN".
A continuously or infinitely variable transmission of the character to which the instant invention pertains comprises a first adjustable rotary sheave or pulley having a shaft which is arranged to be driven by a prime mover, e.g., by the rotary output element, such as a crankshaft or a camshaft, of an internal combustion engine in the power train of a motor vehicle, a second adjustable rotary sheave or pulley having a shaft which can transmit torque to a friction clutch, a hydrokinetic torque converter or another torque receiving constituent of the power train in the motor vehicle, and at least one endless flexible element (such as a belt, particularly a V-belt, or a chain) which is trained over and transmits torque between the two adjustable sheaves,
Each sheave is further combined with or incorporates at least one adjusting system (such as a hydraulically or pneumatically operated cylinder and piston unit) which is designed to move one of the flanges axially of the respective shaft toward or away from the other flange in order to vary the extent of frictional engagement between the flanges and adjacent arcuate portion of the endless flexible element and/or to change the ratio of the transmission.
In addition to the aforementioned U.S. Pat. No. 5,667,448 to Friedmann, transmissions of the above outlined character are disclosed in German patent No. 28 28 347, in published German patent applications Serial Nos. 35 38 884, 40 36 683, 42 01 692 and 42 34 294, and in U.S. Pat. No. 4,046,991 (granted Sep. 10, 1991 to Oswald Friedmann for "CONTINUOUSLY VARIABLE SPEED TRANSMISSION"), U.S. Pat. No. 5,169,365 (granted Dec. 8, 1992 to Oswald Friedmann for "POWER TRAIN"), U.S. Pat. No. 5,217,412 (granted Jun. 8, 1993 to Norbert Indlekofer and Oswald Friedmannn for "CONTINUOUSLY VARIABLE SPEED TRANSMISSION"), U.S. Pat. No. 5,295,915 (granted Mar. 22, 1994 to Oswald Friedmann for "CONTINUOUSLY VARIABLE SPEED TRANSMISSION"), and U.S. Pat. No. 5,711,730 (granted Jan. 27, 1998 to Oswald Friedmann and Armin Veil for "TORQUE MONITORING APPARATUS"). The disclosures of all of the above enumerated patents and patent applications are incorporated herein by reference.
It is considered desirable to apply films or coats of a fluid, such as oil, to those (normally conical) surfaces of the flanges forming part of the sheaves in continuously variable speed transmissions of the above outlined character which come into repeated contact with the endless flexible element when the transmission is in actual use. The purpose of the fluid is to withdraw heat when the transmission is in use and to thus seek to establish a desired (i.e., at least partially satisfactory) frictional engagement between the cooled flanges of the sheaves and the adjacent arcuate portions of the torque transmitting endless flexible element or elements.
As a rule, the fluid coolant is supplied by way of channels or grooves which are provided in the shafts for the flanges of the respective sheaves. A drawback of such conventional proposals is that the normally conical surfaces of the flanges (i.e., the surfaces which repeatedly contact the endless flexible element or elements) are not adequately cooled because they do not receive the required quantities of coolant in actual use of the continuously variable speed transmission and/or because the distribution of supplied coolant is not uniform.
On the other hand, the trend in the automobile industry is toward the construction and assembly of motor vehicles wherein the power train need not undergo any maintenance, or necessitates a minimum of servicing, during the entire useful life of the motor vehicle. For example, it is well known to design, construct and assemble the friction clutches in such a way that they need not be serviced at all during the useful life of the motor vehicle. Such friction clutches can be utilized in conjunction with (for example, they can receive torque from) continuously variable speed transmissions of the type to which the present invention belongs.